Sorbent injection system and method for treating flue gases

Abstract

The present application provides a method of treating flue gas in a duct with an injection system, the flue gas comprising an acid gas and/or one or more metal components, the injection system comprising at least one injection nozzle in communication with an air supply and a supply of sorbent; wherein the method comprises supplying air and sorbent through the nozzle to the duct such that the penetration of the sorbent into the duct is represented by the formula: Y=(Dna(pnVn2/pfVf2)0.5(x/Dn)0.33)/Df where ‘Y’ is the fraction of duct penetration depth of the sorbent when the duct length is ‘x’, ‘Dn’ is the diameter of the nozzle, Df is the depth of the duct, ‘pn’ and ‘pf’ are the densities of the air supply and flue gas, respectively Vn′ and ‘Vf’ are the velocities of the air exiting the nozzle and the flue gas, respectively, and where ‘a’ is between 0.3 and 1.0 and where Y is between 0.3 and 0.8.

1 . A method of treating flue gas in a duct with an injection system, the flue gas comprising an acid gas and/or one or more metal components, the injection system comprising at least one injection nozzle in communication with an air supply and a supply of sorbent; wherein the method comprises supplying air and sorbent through the nozzle to the duct, such that the penetration of the sorbent into the duct is represented by the formula:
     Y =( D   n   a ( p   n   V   n   2   /p   f   V   f   2 ) 0.5 ( x/D   n ) 0.33 )/ D   f      
       where ‘Y’ is the fraction of duct penetration depth of the sorbent when the duct length is ‘x’, ‘D n ’ is the diameter of the nozzle, D f  is the depth of the duct, ‘p n ’ and ‘p f ’ are the densities of the air supply and the flue gas, respectively, ‘V n ’ and ‘V r ’ are the velocities of the air exiting the nozzle and the flue gas, respectively, and where ‘a’ is between 0.3 and 1.0 and Y is maintained between 0.3 and 0.8. 
     
     
         2 . The method according to  claim 1 , wherein the air supply has a mass flow of less than 6%, e.g. less than 3%, of the total flue gas mass flow. 
     
     
         3 . (canceled) 
     
     
         4 . The method of  claim 1  comprising
 adjusting at least one of the velocity and/or pressure of the air exiting the nozzle to control the penetration of sorbent in compliance with the Formula 1, wherein the adjustment is performed through control of a computer processing unit (CPU). 
 
     
     
         5 . The method of  claim 1  wherein at least one of the injection nozzle and the air supply comprises a damper to adjust the pressure and/or velocity of the air supplied to the duct through the nozzle. 
     
     
         6 . (canceled) 
     
     
         7 . (canceled) 
     
     
         8 . The method of  claim 1 , wherein the air supply flow to the at least one nozzle is less than 42.48 m 3 /min (1500 ACFM). 
     
     
         9 . The method of  claim 1 , wherein the velocity of the air and sorbent through the nozzle is less than 150 m/s. 
     
     
         10 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . (canceled) 
     
     
         15 . (canceled) 
     
     
         16 . The method of  claim 1  wherein the sorbent is supplied to the nozzle by source of transport air. 
     
     
         17 . The method of  claim 1 , further comprising injecting water into the duct in the form of liquid droplets or steam to humidify the air in the region of the injection of the sorbent. 
     
     
         18 . (canceled) 
     
     
         19 . (canceled) 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . An injection system for a flue gas duct the injection system comprising:
 at least one injection nozzle in communication with an air supply and a supply of sorbent, the nozzle for the injection of air and sorbent into the duct, a control system to adjust the flow of air from the supply and supply of sorbent such that the penetration of the sorbent into the duct is represented by the formula:
     Y =( D   n   a ( p   n   V   n   2   /p   f   V   f   2 ) 0.5 ( x/D   n ) 0.33 )/ D   f    
   
       where ‘Y’ is the fraction of duct penetration depth of the sorbent when the duct length is ‘x’, ‘D n ’ is the diameter of the nozzle, D f  is the depth of the duct, ‘p n ’ and ‘p f ’ are the densities of the air supply and the flue gas, respectively, ‘V n ’ and ‘V f ’ are the velocities of the air exiting the nozzle and the flue gas, respectively, and where ‘a’ is between 0.3 and 1.0 and where Y is between 0.3 and 0.8. 
     
     
         24 . The injection system according to  claim 23 , wherein the at least one injection nozzle and the air supply comprises a damper to adjust the pressure and/or velocity of the air supplied to the duct through the nozzle. 
     
     
         25 . (canceled) 
     
     
         26 . (canceled) 
     
     
         27 . The injection system according to  claim 24  wherein the damper is controlled through a CPU. 
     
     
         28 . (canceled) 
     
     
         29 . The injection system according to  claim 23 , wherein the at least one nozzle comprises a swirling device, which comprises a rotor having a plurality of radially extending fins angled such that the flow of air through the nozzle causes it to rotate as the flow of the air and sorbent passes therethrough. 
     
     
         30 . The injection system of  claim 29 , wherein the plurality of fins are set at an angle 25° to 50° offset relative to the direction of the air supply and sorbent supply. 
     
     
         31 . The injection system of  claim 30  wherein the angle at which the plurality of fins are offset relative the direction of flow of the air through the nozzle is adjustable. 
     
     
         32 . An injection system for a flue gas duct comprising:
 an injection nozzle in communication with an air supply and a supply of sorbent, wherein the injection nozzle is fitted with a swirling device to increase the angle of dispersion of the sorbent, the swirling device comprising a rotor having a plurality of radially extending fins angled such that the flow of air through the nozzle causes it to rotate as the flow of the air and sorbent passes therethrough.   
     
     
         33 . The injection system of  claim 32  wherein the injection nozzle comprises a damper to adjust the pressure and/or velocity of the air supplied to the duct through the nozzle. 
     
     
         34 . The injection system of  32  wherein the sorbent is supplied to the nozzle by a source of transport air. 
     
     
         35 . The injection system of  claim 32 , wherein the plurality of fins are set at an angle from 1° to 50° off set relative to the direction of the air supply and sorbent supply. 
     
     
         36 . The injection system  claim 32  wherein the angle at which the plurality of fins are offset relative the direction of flow of the air through the nozzle is adjustable either manually or automatically under the control of a control system such as a CPU. 
     
     
         37 . (canceled) 
     
     
         38 . (canceled) 
     
     
         39 . The method according to  claim 1 , wherein the flue gas is from a combustion system for the generation of electrical power, and wherein the flue gas velocity is adjusted by changing the load of the combustion system. 
     
     
         40 . (canceled)